FS5103R 3kg.cm 360 Degree Continuous Rotation Servo
Dimensions: 40.8 × 20.1 × 38 mm
Weight: 36 g
Operating Speed: 0.18sec/60degree (4.8V)0.16sec/60degree (13V)
Stall Torque: 3kg.cm/41.74oz.in(4.8V) 3.2kg.cm/44.52oz.in(6V)
Operating Voltage: 4.8V~6V
Control System: Analog
Direction: CCW
Operating Angle: 360degree
Required Pulse: 500us-2500us
Bearing Type: 2BB
Gear Type: Plastic
Motor Type: Metal
Connector Wire Length: 30 cm
as an example only, see 4935-Pololu for possible wheel fit.